Before you go
You can do a lot before you actually go! Like renting an internet dongle, grab tickets for the places you want to go or simply place stars on a google map. Its a good idea to plan where you want to go. Everything is huge so you'll wanna plan out before going out. And remember to drink a lot of water!
I cant stress this enough. Get an internet dongle! You can get these all around but look through the internet for cheap dongles. You can get these in the airport but its pretty expensive and the dataplans aint that good.